Dyeability or mass coloration of synthetic polyamide

ABSTRACT

1. Synthetic polyamide comprising one or more of the following compounds: 
     a) a compound having at least one sterically hindered amino group,  hereinafter referred to as compounds a)!; or 
     b) a trimesinic acid trialkylamide, at least one alkyl group of which bears at least one free amino and/or alkylamino group  hereinafter referred to as compounds b)!; or 
     c) a trialkylamino-substituted triazine, at least one alkyl group of which carries a free amino and/or alkylamino group  hereinafter referred to as compounds c)!; or 
     d) a dyestuff that is free of sulphonic acid groups and contains at least one group that is reactive to a hydroxy and/or amino group  hereinafter referred to as compounds d)!; or 
     e) a synthetic polyamide containing at least one group that is reactive with a hydroxy and/or amino group  hereinafter referred to as compounds e)!.

This is a continuation of application Ser. No. 08/466,500 filed Jun. 6, 1995, now abandoned, which in turn is a continuation of application Ser. No. 08/144,915 filed Oct. 28, 1993, now abandoned which in turn is a continuation of application Ser. No. 07/727,691 filed Jul. 10, 1991 (now abandoned), which in turn is a continuation-in-part of application Ser. No. 07/467,597 filed Jan. 19, 1990 (now abandoned).

It has been found that the dyeability or mass coloration of synthetic polyamides preferably with anionic dyes can be improved by incorporating into untreated polyamide one or more of the following compounds:

a) a compound having at least one sterically hindered amino, imino or amido group (preferably amino); hereinafter referred to as compounds a)!; or

b) a trimesic acid trialkylamide, or pyromellitic acid tetraalkylamide, at least one alkyl group of which bears at least one free amino, imino, amido and/or alkylamino group hereinafter referred to as compounds b)!; or

c) a trialkylamino, imino or amido substituted triazine, at least one alkyl group of which carries a free amino, imino, amido and/or alkylamino group hereinafter referred to as compounds c)!; or

d) a dyestuff (preferably of the azo-, anthraquinone- or perinone series) that contains at least one group that is reactive to a hydroxy and/or amino group and is preferably free of sulphonic acid groups hereinafter referred to as compounds d)!; or

e) a synthetic modified polyamide (preferably a polymeric or oligomeric isophthalic acid amide or terephthalic acid amide) containing at least one group that is reactive with a hydroxy and/or amino group herein- referred to as compounds e)!.

Compounds containing a sterically hindered amino group are preferably those containing a group of the formula ##STR1## in which R is hydrogen, C₁₋₈ alkyl, C₁₋₈ alkoxy, or --COR₅,

where R₅ is hydrogen, C₁₋₆ alkyl, phenyl, COO(C₁₋₄ alkyl) or NR₁₅ R₁₆ ;

where R₁₅ is hydrogen, C₁₋₁₂ alkyl, C₅₋₆ cycloalkyl, phenyl or (C₁₋₁₂ alkyl)phenyl; and R₁₆ is C₁₋₁₂ alkyl or hydrogen; or

R₁₅ and R₁₆ together with the N atom to which they are attached form a five- to seven-membered ring which may contain an additional N or O atom (preferably forming a piperidine or a morpholine ring).

Preferred groups containing sterically hindered amines are of the formula I to VI ##STR2## in which R is hydrogen, C₁₋₈ alkyl, C₁₋₈ alkoxy, or --COR₅ ;

where R₅ is hydrogen, C₁₋₆ alkyl, phenyl, --COO(C₁₋₄ alkyl) or NR₁₅ R₁₆ ;

where R₁₅ is hydrogen, C₁₋₁₂ alkyl, C5-6cycloalkyl, phenyl or (C₁₋₁₂ alkyl)phenyl; and R₁₆ is C₁₋₁₂ alkyl or hydrogen or

R₁₅ and R₁₆ together with the N atom to which they are attached form a five- to seven-membered ring which may contain an additional N or O atom (preferably forming a piperidine or a morpholine ring); and

Y is the group ##STR3## where CO forms a part of the cyclic structure; each R₆ independently is selected from hydrogen, C₁₋₂ alkyl or phenyl, provided only one group R₆ can be phenyl, or both groups R₆ together form the group --(CH₂)₁₁ --, --(CH₂)_(n) --, --C(CH₃)₂ --, --C(CH₃)₂ --CH₂ CH₂ -- or --C(CH₃)₂ CH₂ CH₂ CH(CH₃)--, and

n is 1 or 2.

Compounds containing groups of formulae III, IV and V are known, for example, from U.S. Pat. No. 4,292,240 and Japanese Kokai 62-190786, the contents of which are are incorporated herein by reference.

More preferred compounds of a) to c) are those of formulae 1 to 38 below: ##STR4## in which each R₃ independently is hydrogen or C₁₋₁₂ alkyl; R₄ is a group of formula α or β ##STR5## where R' is hydrogen, C₁₋₆ alkyl, C₁₋₄ alkoxy or --CO--C₁₋₄ alkyl.

A is C₂₋₃ alkylene;

R₄ ' is of formula α' or α" ##STR6## R₂ is C₁₋₃ alkyl. D₁ is ##STR7## where D₂ is ##STR8## D₃ is ##STR9## D₄ is ##STR10## D₅ is ##STR11## D₆ is ##STR12## and D₇ is ##STR13##

Preferred groups that are reactive to --OH or --NH₂ (of compounds of d) and/or e) are e.g. those known as reactive groups in the chemistry of reactive dyes. More preferably such are cyclic groups having at least 2 nitrogen atoms (separated preferably by one or two carbon atoms), e.g. triazinyl-, pyrimidyl-, quinoxalyl-, quinazolyl groups phthalazinyl, benzoxazolyl and benzthiazolyl groups, bearing 1 to 3 chlorine atoms on the carbon atoms adjacent to the nitrogen atoms.

Additional more preferred reactive groups are of formula i) to xi) ##STR14## in which Z is a halogen (preferably chlorine) or a group of the formula NO⊕ (C₁₋₄ alkyl)₃ or ##STR15## where A⁻ is an anion.

Preferably Alkyl is C₁₋₄ alkyl. Such groups are described in The Chemistry of Synthetic Dyes, Vol. VI, Chapter I--by E. Siegel, editor K. Venkataraman,! Academic Press. (1972);

Chimica, Supplement Marz 1968, Farben Symposium Interlaken, p. 102 et seq--E. Siegel "Chemie der Reactivfarbstoffe" and

Angew. Chem. 76, (1964), No. 10, p. 423 et seq--K.G. Kleb "Ueber neue Reactivfarbstoffe".

Of particular interest are those compounds a) to c) for incorporation into synthetic polyamides having one or two sterically hindered amino groups and one or two groups reactive to --OH and/or --NH₂.

Such compounds having one or two sterically hindered amino groups and one or two groups reactive to OH and/or --NH2 are of formulae 39 to 46 below: ##STR16##

Compounds of formulae 39-46 can be prepared conventionally, e.g. by condensing the appropriate acid chloride or the cyanuric-acid chloride with a free amino or imino group of a sterically hindered amine containing compound in appropriate amounts.

The preferred azo, anthraquinone or perinone dyestuffs of compounds d having groups that are reactive to hydroxy and/or amino groups are preferably those described in Examples 50 to 69 inclusive, hereinafter described.

Examples 50-58 are in 2:1 chromium complex form. ##STR17##

The preferred polymeric isophthalic or terephthalic acid amides of compounds e) and a) respectively are those of formula VII and VIII

    Pa--(R.sub.11).sub.m                                       VII

    Pa--(CO--R.sub.12).sub.m                                   VIII

in which Pa is a nitrogen containing radical of a synthetic polyamide,

R₁₁ is a group attached to the nitrogen atom of the polyamide molecule containing one or more groups reactive to hydroxy and/or amino,

R₁₂ is a group containing a sterically hindered amino group and

m is 1 or 2.

The compounds of formulae VII and VIII can be added to a synthetic polyamide before, during or after the polycondensation synthesis or worked into the molten mass.

The compounds of formula VIII can be produced when a synthetic polyamide having a terminal carboxy group or functional derivative thereof (e.g. the acid chloride or an ester) is reacted during the polycondensation process with one or more amino groups or one or more sterically hindered amino group containing compounds, preferably of aromatic nature. The reactive groups are preferably those described above as groups of formula i-xii.

The compounds of the formula R₁₂ H which are used for producing the compounds of formula VIII have a reactive nitrogen atom that is either an amino group or part of a cycle group, for example a piperazine group. These compounds may also contain one or two sterically hindered nitrogen atoms in a cyclic structure, for example N--C₁₋₄ alkyl or N-acyl substituted 2,2,6,6-tetraalkylpiperidyl-4-groups.

The synthetic polyamides according to the invention can be dyed in the mass with any type of dyestuff, provided that it is stable at high temperatures (of the melt). Preferred dyestuff groups are the monoazo-metal complexes, in particular the chrome complexes that are sufficiently stable at sigh temperatures to be used. Preferred reactive dyestuffs that can be used are the halogen-containing triazinyl or vinyl group containing metallized azo dyestuffs (i.e., those metallized with chromium, nickel or copper). Such reactive dyestuffs have been commercially available for a number of years,

The preparation of modified synthetic polyamides according to the invention can be effected in a conventional manner, preferably by mixing the reactive compounds with molten synthetic polyamide, e.g. in an extruder prior to spinning, or before or during the polycondensation process of the synthetic amide itself.

Generally one uses 0.5 to 5 percent by weight of the compounds a) to e) based on the weight of synthetic polyamides. More preferably 1 to 2 percent by weight of the compounds a) to e) are used.

The synthetic polyamides according to the invention (e.g. containing a compound a) to e)) are outstanding in many respects compared to synthetic polyamide which does not contain a compound a) to e)--hereafter referred to as "untreated polyamide". When dyeing untreated polyamide and polyamide according to the invention with acid dyes is carried out (using the same quantity of dyestuffs on the substrate), a considerably deeper and more brilliant dyeing is obtained with the synthetic polyamides according to the invention than untreated polyamide. Bath exhaustion is noticeably better and the fastnesses, especially vet fastnesses, are improved.

If reactive dyes are used to dye synthetic polyamides according to the invention, in general between 0.05 and 5 percent by weight of the reactive dyes are used based on the weight of synthetic polyamides. More preferably the amounts of reactive dye used is between 0.1 and 3 percent by weight. The dyeings so obtained are also deeper than exhaust dyeings made with the same amound of dye on the untreated; synthetic polyamide.

Further according to the invention, there is provided a process for aftertreating a synthetic substrate, for example polyamide, cellulose and cellulose derivative substrates that have been dyed with anionic dyes characterized in that a solution or dispersion of a compound a) (preferably cycloaliphalic compound containing at least one sterically hindered amine group) is applied thereto.

Preferably the sterically hindered group is a 2,2,6,6-tetramethylpiperidinyl group.

Preferably the substrate is polyamide.

A preferred compound a) is one containing the groups I to VI as defined above.

The compound a) containing groups of formula I are more preferred.

Most preferred compounds a) are of formula XX and XXI ##STR18## in which R₄₀ is a group of the formula ##STR19## where R_(a) is hydrogen, methyl or --CO--CH₃. R₅₀ is chloro or a significance of R₄₀ independent of R₄₀

n_(a) is 2, 3 or 4.

Preferred compounds a) are also those of formula 1 to 38 that contain two or three sterically hindered amine groups.

Preferred dyes that can be used to dye polyamide prior to after treating with compounds a) are selected from:

C.I. Acid Blue 25,40,72,106,126,129,227,230,278,280 and 296

C.I. Acid Yellow 59,112,114,127 and 129

C.I. Acid Red 261 and 404

C.I. Acid Green 40

C.I. Acid Orange 82

C.I. Acid Violet 66

C.I. Acid Brown 28,30 and 289

C.I. Acid Black 58 and 115

C.I. Solvent Yellow 83

C.I. Solvent Red 90:1,91 and 92

C.I. Solvent Black 45

EXAMPLES

In the following examples, all parts and percentages are by weight, and all temperatures are given in degrees celsius.

Example 1

98 parts of poly-ε-caprolactam in granulate form are mixed in a drum mixer with 2 parts of the compound of formula 1a ##STR20## where R'₄ is 2,2,6,6, tetramethylpiperidinyl-4,

(prepared by the condensation of 2 moles of 2,2,6,6-tetramethyl-4-aminopiperidine with 1 mol of 2,4,6-trichlorotriazine in 5 moles of toluene, after which the solution is boiled under reflux for 10 hours, the residue is filtered, washed with acetone, then heated with aqueous NaOH at pH 12, filtered, washed and dried) in powder form. The powder is mixed in a drum mixer and disperses very rapidly and very evenly and adheres to the granulate. After ca. 10 minutes, the mixture is dried for 8 hours at 120°, added to a melt spinning machine and after leaving standing for 8 minutes at 275-280° under a nitrogen atmosphere, is spun into fibres.

The fibres thus obtained may be dyed or printed by known processes tel quel or after processing into yarns, or woven or knit fabrics as is usual for polyamide fibre material, using the appropriate acid dyes, e.g. the dyes C.I. Acid Red 216, C.I. Acid Violet 66, C.I. Acid Yellow 155, C.I. Acid Blue 230, C.I. Acid Red 129, C.I. Acid Yellow 184, C.I. Acid Red 119 or C.I. Acid Blue 80.

The dyeings thus obtained have increased depth of colour (compared with the same dyeing made on untreated poly-ε-caprolactam), a good brilliance and good wet fastness properties.

An appropriate amount of the following compounds may be incorporated into synthetic polyamide material as described in example 1 in place of the compound of formula 1a. ##STR21##

In Examples 1 to 6, R₄ ' is 2,2,6,6-tetramethylpiperidinyl-4.

Examples 7-11

The following compounds can be prepared by a method analogous to that of Example 1 from appropriate reactants. ##STR22##

The products of Examples 7 to 11 can be washed into polyamide that can be used for spinning.

Example 12

a) Production of 1,3,5-tri-(2',2',6',6'-tetramethylpiperidyl-4')-trimesic acid amide

42.0 g of trimesic acid are heated for 5 hours at 80° with 144.0 ml of thionyl chloride in the presence of catalytic quantities (3 ml) of dimethylformamide and then the excess thionyl chloride is distilled off. The trimesic acid trichloride thus formed is dissolved in 500 ml of dioxane, then a total of 187.2 g of 2,2,6,6-tetramethyl-4-aminopyridine is added dropwise whilst stirring, whereby dioxane (2000 ml in all) is constantly added to allow the reaction mixture, whose temperature should never exceed 30° C., to remain stirrable. The reaction mixture is subsequently boiled for 48 hours with reflux cooling, the residue is filtered, washed with acetone, dissolved in ca. 1000 ml of water, precipitated again with soda solution (at pH 10 to 11), filtered, the residue washed with water and vacuum-dried (yield 89.2 g=72% of a white powder having a melting point of >320° C.).

b) Production of a modified synthetic polyamide

100 parts of poly-ε-caprolactam in powder form are mixed with 1.0 parts of the compound obtained under 12 a) above in a drum mixer. After a short time, the powder is dispersed very evenly. After ca. 10 minutes, the mixture is dried for 16 hours at 120°, added to a melt spinning machine, and after leaving for 8 minutes at 275-280° C. under a nitrogen atmosphere, is spun into fibres.

The fibres are dyed conventionally by exhaustion with 0.5% with the dyestuff C.I. Acid Red 216.

Very evenly red-dyed fibres are obtained having excellent brilliance, with very good washing, light and rubbing fastness properties. Poly-ε-caprolactam fibres which have not been modified according to the invention but are dyed in the same way have considerably less depth of colour and brilliance and noticeably reduced fastness.

Instead of C.I. Acid Red 404, an appropriate amount of one of the following dyestuffs can also be used

C.I. Acid Blue 80,

C.I. Acid Yellow 129,

C.I. Acid Violet 66,

C.I. Acid Blue 129,

C.I. Acid Green 28 and

C.I. Acid Red 119.

In a method analogous to that of Example 12, an appropriate amount of any one of Compounds 1 to 21 defined above can be worked into polyamide in the mass, which is then spun into fibres and dyed with one of the acid dyes described above.

Example 13

872 parts of N-methylpyrrolidone are charged into a 1.5 litre reaction vessel. 28.35 parts (0.2625 moles) of 1,4 diaminobenzene are added at 20° (±2°) to this reaction vessel. The mixture is then cooled to 0° and 50.75 parts (0.25 moles) of terephthalic acid dichloride is added portion by portion, stirring well, and the mixture is held at a constant temperature. When the addition is completed, the mixture is heated over 4 hours from 20-80° in stages. 5.3 parts (0.0125 moles) of 1'chloro-3,5-bis(2',2',6',6'-tetramethylpiperidyl-4'amino)-triazine are added and the mixture is stirred at 100° for 4 hours.

The resulting solid is then filtered and washed with water and separated from the filtrate. It is then dried under vacuum at 100° C. under 20 mm of mercury (Hg). 66.0 parts of a polyamide results as a light beige powder which has good dyeing properties.

This modified polymer can be incorporated into untreated polyamide by conventional master batch methods.

Examples 14-32

Example 13 can be repeated by condensing 0.2625 moles of the diamine of column 1 of Table 1 below, with 0.25 moles of the dicarboxylic acid dichloride of column 2 of Table 1 below and 0.0125 moles of the chloro-compound of column 3 of Table 1 below. R₄ ' in the following tables is always the group 2,2,6,6-tetramethylpiperidyl-4 and R₅ is the group 1,2,2,6,6-pentamethylpiperidyl-4.

                                      TABLE 1     __________________________________________________________________________     Example          Column 1 Column 2    Column 3     No.  Amine    Carboxylic acid dichloride                               Chloro-compound     __________________________________________________________________________     14   1,3 diaminobenzene                   isophthalic acid dichloride                               2 chloro-4,6-bis(2',2',6',6-                   (benzene 1,3-dicarboxylic                               tetramethylpiperidyl-4'amino)-                   acid dichloride)                               triazine     15   "        isophthalic acid dichloride (benzene 1,3-dicarboxylic acid                   dichloride)                               1 #STR23##     16   1,4 diaminobenzene                   terephthalic acid dichloride (benzene 1,4-dicarboxylic acid                   dichloride                               1 #STR24##     17   "        terephthalic acid dichloride (benzene 1,4-dicarboxylic acid                   dichloride                               2 #STR25##     18   1,3 diaminobenzene                   isophthalic acid dichloride                               2 #STR26##     19   "            "                               3 #STR27##     20   1,4 diaminobenzene                   terephthalic acid dichloride                               3 #STR28##     21   1,4 diaminobenzene                   terephthalic acid dichloride                               4 #STR29##     22   1,3 diaminobenzene                   isophthalic acid dichloride                               4 #STR30##     23   "            "                               5 #STR31##     24   1,4 diaminobenzene                   terephthalic acid dichloride                               5 #STR32##     25   "            "       Cl--CH.sub.2 CONH--R.sub.4 '     26   1,3 diaminobenzene                   isophthalic acid dichloride                               "     27   "            "                               6 #STR33##     28   1,4 diaminobenzene                   terephthalic acid dichloride                               6 #STR34##     29   "            "                               7 #STR35##     30   1,3 diaminobenzene                   isophthalic acid dichloride                               7 #STR36##     31   1,3 diaminobenzene                   isophthalic acid dichloride                               8 #STR37##     32   1,4 diaminobenzene                   terephthalic acid dichloride                               8 #STR38##     __________________________________________________________________________

Example 33

Example 13 is repeated using 27.0 parts (0.25 moles) of 1,4-diaminobenzene (instead of 28.35 parts in Example 13); 51 parts (0.25125 moles) terephthalic acid dichloride (instead of 50.75 parts in Example 13); and 0.3 parts (0.00125 moles) of 1-amino-4-(2',2',6',6'-tetramethylpiperidinyl-4'-amino)benzene (instead of 53 parts of 1-chloro-3.5-bis(2',2',6',6'-tetramethylpiperidinyl-4'-amino) triazine.

61.3 parts of a modified polyamide results with good properties.

Examples 34-48

Example 33 is repeated condensing 0.25 moles of the amine of column 1, 0.25125 moles of the dichloride of column 2 and 0.00125 moles of the amino compound of column 3 of Table 2 below. R₄ ' is 2,2,6,6 tetramethylpiperidinyl-4.

                                      TABLE 2     __________________________________________________________________________     Example          Column 1 Column 2    Column 3     No.  Amine    dichloride  Amine compound     __________________________________________________________________________     34   1,3 diaminobenzene                   isophthalic acid dichloride                               9 #STR39##     35   "        "                               0 #STR40##     36   1,4 diaminobenzene                   terephthalic acid dichloride                               0 #STR41##     37   "        "                               1 #STR42##     38   1,3 diaminobenzene                   isophthalic acid dichloride                               1 #STR43##     39   "        "                               2 #STR44##     40   1,4 diaminobenzene                   terephthalic acid dichloride                               2 #STR45##     41   "        "                               3 #STR46##     42   1,3 diaminobenzene                   isophthalic acid dichloride                               3 #STR47##     43   "        "                               4 #STR48##     44   1,4 diaminobenzene                   terephthalic acid dichloride                               4 #STR49##     45   "        "                               5 #STR50##     46   1,3 diaminobenzene                   isophthalic acid dichloride                               5 #STR51##     47   "        "                               6 #STR52##     48   1,4 diaminobenzene                   terephthalic acid dichloride                               6 #STR53##     __________________________________________________________________________

Example 49

98 parts of a granulate of Nylon 6 is mixed for 1 hour with 2% of 2-chloro-4,6-bis-(2',2',6',6'-tetramethylpiperidyl-4'-amino)triazine in a powder mixer (Rhoenrad) then this is treated in a laboratory extruder (MARIS TM 33 V/32 D) and it is then spun into fibres under the following conditions

Speed of the screw: 321

Rate of dosage: 40%

Rate of extrusion: 23 kg/h

Pressure: 2 bar

Temperature in zone 1: 168°

2-6: 300°

7: 259°

8: 256°

9: 263°

The resulting fibres can be used as such or can be used in the form of a yarn or web or piece such as polyamide fibre material. The fibres can be dyed with suitable acid dyes, for example

C.I. Acid Red 404,

C.I. Acid Violet 66,

C.I. Acid Yellow 129,

C.I. Acid Blue 129,

C.I. Acid Green 28

C.I. Acid Red 119 or

C.I. Acid Blue 80.

Exhaust-Dyeing can be carried out by known methods. The fabrics can also be printed. The resulting dyeings show excellent depth of color (compared to the same dye without the modifiedpoly-ε-caprolactam. They have good brilliance and good wet fastness properties.

Example 50

Example 1 is repeated, but instead of the 2 parts of the compound of formula 1a, 1.5 parts of the 1:2-chrome complex of the dyestuff of formula 50a ##STR54## are used. The resultant dyeings result in very full, brilliant and fast red dyed fibres.

Example 51

Example 50 is repeated using an equivalent amount of the 1:2-chrome complex of the dyestuff of formula 51a ##STR55## Deep, brilliant and very fast dyed fibres are similarly obtained.

Examples 52-69

By a method analogous to that of Example 50, using a molar equivalent amount of one of the following compounds of Table 3 below instead of the component of formula 50a, fast and brilliant coloured fibre material can be produced. The colours of the resulting dyeings are also shown in Table 3.

Examples 52-58 are 1:2 chromium complexes

                                      TABLE 3     __________________________________________________________________________     Example          Compound                            Colour     __________________________________________________________________________     52          7 #STR56##                          red     53          8 #STR57##                          orange-red     54          9 #STR58##                          red     55          0 #STR59##                          "     56          1 #STR60##                          red     57          2 #STR61##                          "     58          3 #STR62##                          "     59          4 #STR63##                          yellow     60          5 #STR64##                          yellow     61          6 #STR65##                          yellow     62          7 #STR66##                          orange-red     63          8 #STR67##                          orange     64          9 #STR68##     65          0 #STR69##     66          1 #STR70##                          blue     67          2 #STR71##                          blue     68          3 #STR72##                          red     69          4 #STR73##                          red     __________________________________________________________________________

Example 70

By a method analogous to that of Example 12a, 2 moles of the compound of formula 70a ##STR74##

(2,2,5,5-tetramethyl-3-carboxy-pyrrolidine described in Japanese Kokai 60-190786) is reacted with 1 mole of thionylchloride to form the acid chloride. This is dissolved in dioxan and is condensed with 1 mole of 1,4-diaminobenzene. The reaction product is filtered, treated with aqueous alkali, filtered again, washed and dried under vacuum. The resulting product is treated according to the method of Sample 12b and modified poly-ε-caprolactam fibres result, which can be dyed with the dyestuffs described in Example 12b. The dyeings that result are brilliant in color and have good fastness properties.

Examples 71-73

Example 70 is repeated using molar equivalents of one of the following ##STR75##

Examples 74-77

Example 70 is repeated using molar equivalents of the following:

Example 74: 2,2,5,5-tetramethyl-3-carboxy-pyrrolidine

Example 75: 1,2,2,5,5-pentamethyl-3-carboxy-pyrrolidine

Example 76: 2,2,5,5-tetramethyl-3-carboxy-pyrroline and

Example 77: 1,2,2,5,5-pentamethyl-3-carboxy-pyrroline.

These are reacted with 1,6-hexamethylene diamine and produce modified polyamide fibres having good dyeing properties.

Examples 78 and 79

Example 12 is repeated using 2 moles of 2,2,6,6-tetramethylpiperazine-3-one with 1 mole of terephthalic acid dichloride. This produces poly-ε-caprolactam (Nylon 6) which can be. spun into fibres. A fibre material results with very good dyeability and resulting dyes are of very high quality.

Example 12 can also be repeated using a condensation product derived from 2 moles of 1,2,2,6,6-pentamethylpiperazine-3-one with 1 mole of isophthalic acid dichloride.

Examples 80 and 81

The addition product of 2 moles of the compound of Formula 80a ##STR76## and 1 mole of bis-(4-isocyanatophenylene)-methane (from Example 2 of U.S. Pat. No. 4,816,585) can be worked into Nylon 6 according to the method of Example 12b to produce a polyamide of similar quality to that of Example 12b.

A similar effect can be produced by using the addition product of 1 mole of 1,6-diisocyanatohexamethylene and 2 moles of the above mentioned product of Formula 80 described above.

Examples 82 and 83

1 mole of 2,4,6-trichloratriazine can be condensed with 1 mole of 2,2,6,6-tetramethylene-4-aminopiperidine and 1 mole of 2,2,6,6-tetramethylpiperazine-3-one according to the method of Example 1.

1 mole of 2,4,6-trichloro triazine can be condensed with 1 mole of 3,3,5,5,7-pentamethyl-1,4-diazepine-2-one (described in U.S. Pat. No. 4,292,240) and 1 mole of 2,2,6,6-tetramethyl-4-aminopiperidine.

Either reaction product can be worked into poly-ε-caprolactam and the resulting polyamide fibres have good dyeing properties.

Example 84

a) Non-matted polyamide-6 (Grilon A22 in the form of chips from Emser Werke AG, having a solution viscosity 2.01) is dyed with 10% (based on the weight of substrate) of C.I. Acid Blue 129 in the presence of 4 g/l of sodium phosphate at a good to liquor ratio of 1:3. Dyeing was carried out for 2 hours at boiling.

After filtering and washing with water at room temperature after treating is carried out as follows:

b) 500 g PA-6 chips (previously bath-dyed with C.I. Acid Blue 129) were suspended under stirring in an aqueous solution (1 l.) containing 5% bis protonated 2,4-bis-(2',2',6',6'-tetramethyl piperidyl-4'-amino)-6-chlorotriazine acid for protonation used: HCl or acetic acid! and heated at 60° C. for 1 hours, filtered, washed with water, dried and then spun to fiber. 

What is claimed is:
 1. Synthetic polyamide comprising:a.) A compound having at least one sterically hindered amine group of the formula ##STR77## In which R₄ is a group of formula α ##STR78## where R' is hydrogen, C₁₋₆ alkyl, C₁₋₄ alkoxy or --CO--C₁₋₄ alkyl.
 2. A process for aftertreating a synthetic substrate that has been dyed with one or more anionic dyes characterized in that a solution or a dispersion of a compound a) as defined in claim 1 is applied to the substrate. 